Many types of machines, apparatus and structural installations incorporate articulated joints to non-rigidly connect together two adjacent bodies when it is desired, or necessary, to have one or both of the bodies pivot with respect to the other body, or to a third body.
At times a conduit, such as a fluid conduit, must extend from or between, and be secured to, two bodies connected together by an articulated joint. Since the two bodies pivot with respect to one another at the articulated joint, it is essential that the conduit include a non-rigid yieldable section at, or in the vicinity of, the articulated joint which will not significantly interfere with the pivoting action between the bodies.
There is much present interest in fluid conduit articulated joint bypass systems by oil companies engaged in offshore exploration, development and production. This is because such endeavors often require the utilization of a deep water offshore buoyant column or tower pivotally secured in place at its lower end by an articulated joint operatively connected to a base anchored to the sea floor. Oil or gas lines or conduits desirably run along the sea floor and then up the column to the column top. From the column top, the oil or gas lines extend to a ship moored to the column. The mechanism used to moor the ship can include an articulated joint at the column top so that the ship is free to pitch and roll relative to the column. Since a fluid conduit must often extend from the column top to the ship, it is necessary that the fluid conduit include a means by which fluid can be conveyed from a conduit on the column past the articulated joint to a conduit on a ship mooring boom or yoke or to the ship itself.
Reid U.S. Pat. No. 4,010,500 discloses the use of a cardan type universal joint at the top and bottom of an offshore mooring column. The patent also discloses fluid coupling of a pipe from one side of the cardan joint to the other side by passing a conduit or pipe elbow through hollow pins of the cardan joint positioned 90.degree. from each other. Conduit or pipe sections communicate with each end of the elbow through suitable fluid swivels so that pivotal movement of the column to the base, or the ship mooring yoke to the column, is unrestrained yet a fluid tight coupling between conduit sections is achieved. The conduit bypass system shown in Reid has a disadvantage in that it directly involves the bypass conduit in the structure of the articulated joint. In addition, it cannot be used when the column is arranged to rotate about a vertical axis and also pivot about a horizontal axis.
Other patents disclosing various types of articulated joint by-pass conduit arrangements are the U.S. Pat. No. 4,026,119 of Dotti; U.S. Pat. No. 4,029,039 van Heijst; U.S. Pat. No. 4,165,108 Saint-Palais;U.S. Pat. No. 3,641,602 Flory; U.S. Pat. No. 3,984,059 Davis; and U.S. Pat. No. 4,142,820 Tuson (which is similar to Reid, supra).